Petresin 20IU Injection is used in the treatment of diabetes insipidus, bleeding esophageal varices (bleeding from dilated veins in the food pipe leading to your stomach), and low blood pressure. Petresin 20IU Injection is generally administered by a doctor or a nurse. You should not self-administer this medicine at home. Your doctor will decide the dose and how often you should take them. Using this medicine can cause some common side effects such as decreased cardiac output, slow heart rate, tachyarrhythmias, decreased sodium level in the blood, and ischemia. Let your doctor know if any of these side effects do not go away or get worse. Before using this medicine, inform your doctor if you have any problems with your heart, liver, or kidneys. You should also tell your doctor all the other medicines you are taking. This medicine is not recommended for children and adolescents.